Wrench for providing two operative modes

Description

BACKGROUND OF INVENTION

1. FIELD OF INVENTION

[0001] The present invention relates to a wrench for providing two operative modes for driving a fastener.

2. RELATED PRIOR ART

[0002] A selective one-way wrench includes a handle, a head formed on the handle, a mandrel, a transmitting unit and a direction-selecting unit operable for selecting one of two directions in which the head drives the mandrel through the transmitting unit.

[0003] The wrench can be used together with a socket to slack or tighten a fastener. The mandrel is inserted in an end of the socket while the fastener is inserted in an opposite end of the socket.

[0004] To slack the fastener, the wrench is used to exert a large torque on the fastener initially. Once the fastener is slacked, it would be faster to drive the fastener with a bare hand than with the wrench.

[0005] To tighten the fastener, it would be faster to drive the fastener with a bare hand than with the wrench initially. At a final stage, the wrench is used to exert a large torque on the fastener.

[0006] There are wrenches each including a handle, a head formed on the handle, a mandrel, a transmitting unit, a direction-selecting unit operable for selecting one of two directions in which the head drives the mandrel through the transmitting unit and a shaft connected to the transmitting unit. At an initial stage of a slacking operation or a final stage of a tightening operation, the handle is operated to drive operated to drive the mandrel through the transmitting unit. For the rest of the slacking or tightening operation, the shaft is operated to drive the mandrel through the transmitting unit. Such wrenches can be found in EP 0486710, US 454567, US 5105688, US 6070499, WO 8803999, WO 9207692 and Taiwanese Patent Publication No. 494828 for example. In each of these wrenches, the head is secured to the handle and this could be inconvenient when it is used in limited space. An example for wrench with a swing head structure which allows output of two kinds of torque is shown US 2005/0155468 A1. However, the structure shown in D1 uses a transmitting unit transmitting the torque of the handle via a gear train in a direction along an extension of the longitudinal axis of the handle and the connected shaft. Accordingly, the transmission of the torque to the head leads to a design where some of the gears cannot be formed in a closed ring shape which makes the production complex and the operation difficult.

[0007] The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.

SUMMARY OF INVENTION

[0008] It is the primary objective of the present invention to provide a two-mode wrench with a head pivotally connected to a handle which has a simple design and is reliable in operation. Such an object is achieved by a wrench according to claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0009] To achieve the foregoing objective, the wrench includes a handle, a yoke, a shaft, a head, a mandrel, a first transmitting unit and a second transmitting unit. The shaft includes a first section securely connected to the handle and a second section rotationally inserted in the yoke. The head is pivotally connected to the yoke. The mandrel is inserted through the head. The first transmitting unit can be used to transmit a small torque to the mandrel from the handle spun relative to the yoke. The second transmitting unit can be used together with the first transmitting unit to transmit a large torque to the mandrel from the handle pivoted together with the yoke.

[0010] Other objectives, advantages and features of the present invention will be apparent from the following description referring to the drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0011] The present invention will be described via detailed illustration of the preferred embodiment referring to the drawings.

Fig. 1 is a perspective view of a two-mode wrench according to the preferred embodiment of the present invention.

Fig. 2 is a cross-sectional view of the wrench shown in Fig. 1.

Fig. 3 is an enlarged, partial view of the wrench shown in Fig. 2.

Fig. 4 is an enlarged, partial, cutaway view of the wrench shown in Fig. 1.

Fig. 5 is a partial, exploded view of the wrench shown in Fig. 1.

Fig. 6 is a perspective view of the wrench shown in Fig. 5.

Fig. 7 is another enlarged, cross-sectional view of the wrench shown in Fig. 1.

Fig. 8 is an enlarged, partial, cutaway view of the wrench shown in Fig. l.

Fig. 9 is an enlarged, partial, cutaway view of the wrench in another position than shown in Fig. 8.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0012] Referring to Figs. 1 through 7, a two-mode wrench 100 includes a handle 10, a yoke 20, a head 30 pivotally connected to the yoke 20, a mandrel 40, a direction-selecting unit 50, a first transmitting unit, a second transmitting unit and a clutch 70 according to the preferred embodiment of the present invention. The wrench 100 is used with a socket to drive a fastener such as a nut and a screw. The mandrel 40 is inserted in a first cavity defined in the socket while the fastener is inserted in a second cavity defined in the socket. The direction-selecting unit 50 is operable to choose from two directions in which the wrench 100 rotates the fastener. At an initial stage of a slacking operation or a final stage of a tightening operation where a large torque is needed, the handle 10 is operated to drive the mandrel 40 via the first and second transmitting units. For the rest of the slacking or tightening operation, the handle 10 is operated to drive the mandrel 40 via the first transmitting unit only.

[0013] Referring to Figs. 2 through 4, the yoke 20 includes two branches 21 extended from two opposite sides thereof, a tunnel 22 defined therein and a chamber 23 defined in one of the branches 21. The chamber 23 is in communication with the tunnel 22. The head 30 is pivotally connected to the branches 21 with an axle 15 and a pin 24. The clutch 70 is located in the head 30 and will be described in detail later.

[0014] The head 30 includes a space 32 centrally defined therein. There are grooves 33 longitudinally defined in the wall of the space 32 so that the grooves 33 are in communication with the space 32. A groove 34 is annularly defined in the wall of the space 32 so that the groove 34 is in communication with the space 32 and the grooves 33. Two apertures 31 are transversely defined in the head 30 so that the apertures 31 are in communication with the space 32.

[0015] The axle 15 includes a first reduced end 16, a second reduced end 19 and a middle section 17 formed between the first reduced end 16 and the second reduced end 19. The first reduced end 16 of the axle 15 is inserted through the chamber 23 and connected to a plug 161. The middle section 17 of the axle 15 is inserted through one of the apertures 31 so that the second reduced end 19 of the axle 15 is located in the space 32. The middle section 17 of the axle 15 is formed with teeth 18. The teeth 18 are operatively connected to the clutch 70.

[0016] The pin 24 includes an enlarged end, a reduced end 26 and a middle section 25 between the enlarged and reduced ends. The enlarged end of the pin 24 is a threaded portion engaged with a screw hole defined in the related branch 21 of the yoke 20. The middle section 25 of the pin 24 is inserted through the other aperture 31 so that the reduced end 26 of the pin 24 is located in the space 32.

[0017] Referring to Figs. 5 through 7, the periphery of the mandrel 40 is non-circular. The mandrel 40 includes a tunnel 44 axially defined therein and an aperture 48 transversely defined therein so that they are in communication with each other. The mandrel 40 includes a frame 43 formed thereon.

[0018] A ball 41 includes a portion located in the tunnel 44 and another portion exposed to the exterior of the mandrel 40 through the aperture 48. The tunnel 44 includes a narrow lower section, a wide upper section and an annular shoulder between the lower and upper sections. A spring 45 is located in the upper section of the tunnel 44. A button 42 is formed on a rod 46. A recess 47 is defined in the rod 46. The rod 46 is inserted in the tunnel 44 so that it is in contact with the ball 41. The rod 46 is inserted through the spring 45. The spring 45 is compressed between the button 42 and the annular shoulder.

[0019] When the button 42 is pushed, a first portion of the ball 41 can be located in the recess 47 so that an opposite second portion of the ball 41 can be located in the aperture 48. Thus, the mandrel 40 can be inserted in the first cavity defined in the socket. On being released, the button 42 is lifted with the spring 45. The first portion of the ball 41 is abutted against the rod 46, thus keeping the second portion of the ball 41 exposed to the exterior of the mandrel 40. The second portion of the ball 41 is abutted against an internal side of the socket, thus keeping the socket connected to the mandrel 40. Thus, the nut or screw can be driven with the mandrel 40 through the socket.

[0020] The direction-selecting unit 50 includes a knob 51, a pusher 56 and a ring 60. The knob 51 includes a cavity 52 defined in a side, an aperture 53 defined therein and wedges 54 formed on an opposite side. The pusher 56 includes wedges 57 formed on a side and legs 58 formed on an opposite side. The ring 60 includes an aperture 61 defined therein, two planar faces 62 formed thereon and two recesses 63 each defined in a related one of the planar faces 62.

[0021] One of the apertures 61 receives the second reduced end 19 of the axle 15 while the other aperture 61 receives the reduced end 26 of the pin 24. Thus, the ring 60 is connected to the yoke 20. The pusher 56 is inserted through the aperture 61 of the ring 60. The knob 51 is located on the pusher 56 so that the wedges 54 of the knob 51 are engaged with the wedges 57 of the pusher 56. Thus, the pusher 56 is moved with the knob 51 when the knob 51 is rotated relative to the pusher 56.

[0022] The first transmitting unit includes a shaft 11, a gear train 12 and toothed wheels 80 and 90. The shaft 11 includes a section securely inserted in the handle 10 and another section rotationally inserted in the tunnel 22 defined in the yoke 20. The gear train 12 is located in the chamber 23. The gear train 12 includes an active gear 13 and passive gears 14. The active gear 13 is securely connected to the shaft 11. A first one of the passive gears 14 is engaged with the active gear 13. A last one of the passive gears 14 is securely provided on the first reduced end 16 of the axle 15. Thus, when the handle 10 is rotated relative to the yoke 20, the shaft 11 rotates the axle 15 through the gear train 12.

[0023] The toothed wheel 80 includes teeth 81 formed on a side and ratchets 82 formed on an opposite side. The toothed wheel 80 includes an aperture 83 defined therein corresponding to the non-circular periphery of the mandrel 40 and four recesses 84 defined therein corresponding to the legs 58 of the pusher 56. The mandrel 40 is inserted through the aperture 83 so that the mandrel 40 and the toothed wheel 80 can only be rotated together. The legs 58 are inserted through the recesses 84. The teeth 81 of the toothed wheel 80 are engaged with the teeth 18 of the axle 15.

[0024] The toothed wheel 90 includes an aperture 91 defined therein corresponding to the non-circular periphery of the mandrel 40 and ratchets 92 formed on a side. The mandrel 40 is inserted through the aperture 91 so that the mandrel 40 and the toothed wheel 90 can only be rotated together.

[0025] The second transmitting unit includes a toothed wheel 85. The toothed wheel 85 includes ratchets 88 formed on a side, ratchets 89 formed on an opposite side, an aperture 94 defined therein, an annular flange 86 on the wall of the aperture 94 and blocks 87 formed on the periphery thereof. The mandrel 40 is inserted through the aperture 94. The blocks 87 are located in the grooves 33 so that the toothed wheel 85 can be moved but not rotated in the head 30. The ratchets 88 of the toothed wheel 85 can be engaged with the ratchets 82 of the toothed wheel 80. The ratchets 89 of the toothed wheel 85 can be engaged with the ratchets 92 of the toothed wheel 90.

[0026] The clutch 70 includes a ring 71, springs 72 and 73 and a C-clip 74. The ring 71 and the spring 72 are located against each other and between the toothed wheels 80 and 85. The spring 72 is located in the aperture of the second ring 85 and abutted against the annular flange 86. Thus, the spring 72 is compressed between the toothed wheels 80 and 85. The spring 73 is compressed between the toothed wheels 85 and 90. A C-clip 74 is located in the groove 34 for retaining the clutch 70 within the head 30.

[0027] Referring to Figs. 6 and 8, to provide a small torque for driving the fastener clockwise, the handle 10 is rotated relative to the yoke 20 so that the shaft 11 is rotated relative to the yoke 20. The shaft 11 rotates the toothed wheel 80 via the gear train 12. The toothed wheel 80 rotates the mandrel 40. The ratchets 82 of the toothed wheel 80 rattle on the ratchets 88 of the toothed wheel 85.

[0028] In any attempt to rotate the toothed wheel 80 counterclockwise relative to the toothed wheel 85, the ratchets 82 are locked with the ratchets 88. The toothed wheel 80 cannot rotate relative to the toothed wheel 85. Therefore, the toothed wheel 80 cannot rotate the mandrel 40.

[0029] To provide a large torque for tightening the fastener, the handle 10 and the yoke 20 are rotated together. The yoke 20 rotates the head 30. The head 30 rotates the toothed wheel 85. The toothed wheel 85 rotates the toothed wheel 80 because the ratchets 88 are engaged with the ratchets 82. The toothed wheel 80 rotates the mandrel 40.

[0030] Referring to Fig. 9, to slack the fastener, the knob 51 is rotated relative to the pusher 56. The knob 51 moves the pusher 56 downwards due to the engagement of the wedges 57 of the former with the wedges 54 of the latter. The pusher 56 pushes down the toothed wheel 85 due to the contact of the legs 58 of the pusher 56 with the annular flange 86 of the toothed wheel 85. The ratchets 88 of the toothed wheel 85 are disengaged from the ratchets 82 of the toothed wheel 80 while the ratchets 89 of the toothed wheel 85 are engaged with the ratchets 92 of the toothed wheel 90.

[0031] To provide a large torque for slacking the fastener, the handle 10 and the yoke 20 are rotated together. The yoke 20 rotates the head 30. The head 30 rotates the toothed wheel 85. The toothed wheel 85 rotates the toothed wheel 90 for the engagement of the ratchets 89 with the ratchets 92. The toothed wheel 90 rotates the mandrel 40.

[0032] To provide a small torque for driving the fastener counterclockwise, the handle 10 is rotated relative to the yoke 20 so that the shaft 11 is rotated relative to the yoke 20. The shaft 11 rotates the toothed wheel 80 via the gear train 12. The toothed wheel 80 rotates the mandrel 40.

[0033] In any attempt to rotate the toothed wheel 85 clockwise, the ratchets 92 of the toothed wheel 90 are locked with the ratchets 89 of the toothed wheel 85. The toothed wheel 90 cannot rotate clockwise relative to the toothed wheel 85. Therefore, the toothed wheel 90 cannot rotate the mandrel 40.

[0034] The present invention has been described via the detailed illustration of the preferred embodiment. Those skilled in the art can derive variations from the preferred embodiment without departing from the scope of the present invention. Therefore, the preferred embodiment shall not limit the scope of the present invention defined in the claims.

Claims

1. A wrench comprising:

a handle (10);

a yoke (20);

a shaft (11) comprising a first section securely connected to the handle and a second section rotationally inserted in the yoke (20);

a head (30) pivotally connected to the yoke (20);

a mandrel (40) inserted through the head (30);

a first transmitting unit for transmitting a small torque to the mandrel (40) from the handle (10) spun relative to the yoke (20);

a second transmitting unit in cooperation with the first transmitting unit to transmit a large torque to the mandrel (40) from the handle (10) pivoted together with the yoke (20);

a pin (24) comprising a first end inserted in the yoke (20) and a second end inserted in the head (30); and

an axle (15) comprising a first end inserted in the yoke (20) and a second end inserted in the head (30) wherein the first transmitting unit comprises:

a toothed wheel (80) securely provided around the mandrel (40) and engaged with the axle (15); and

a gear train (12) comprising a first gear securely provided around the shaft and a last gear securely provided around the axle (15),

characterized in that the second transmitting unit comprises a toothed wheel (85) engaged with the toothed wheel (80) of the first transmitting unit and non-rotationally connected to the head (30).

2. The wrench according to claim 1, wherein the head (30) comprises grooves (33) defined in an internal side, and the toothed wheel (85) of the second transmitting unit comprises blocks (87) located in the grooves (88) of the head.

3. The wrench according to claim 1 comprising a direction-selecting unit (50) operable to choose from two directions in which the wrench rotates the fastener.

4. The wrench according to claim 3, wherein the direction-selecting unit (50) comprises a toothed wheel movable between a first position and a second position in the head (30) and formed with a first group of ratchets on a side and a second group of ratchets on an opposite side, and the first transmitting unit comprises:

a first toothed wheel (80) securely provided around the mandrel (40) and formed with a group of ratchets for engagement with the first group of ratchets of the toothed wheel of the direction-selecting unit in the first position;

a second toothed wheel (90) securely provided around the mandrel (40) and formed with a group of ratchets for engagement with the second group of ratchets of the toothed wheel of the direction-selecting unit (50) in the second position; and

a gear train (12) comprising a first gear securely provided around the shaft and a last gear securely provided around the axle (15).

5. The wrench according to claim 4, wherein the direction-selecting unit (50) comprises:

a knob (51) rotationally provided on the head (30) and formed with wedges (57) on a side; and

a pusher (56) movably but non-rotationally located in the head (30) and formed with wedges (57) engaged with the wedges (57) of the knob (51) and legs (58) in contact with the toothed wheel of the direction-selecting unit.

6. The wrench according to claim5, comprising a clutch (70) in cooperation with the direction-selecting unit (50) for smoothly moving the toothed wheel of the direction-selecting unit between the first and second positions.

7. The wrench according to claim6, wherein the clutch (70) comprises:

a first spring (72) compressed between the first toothed wheel (80) of the first transmitting unit and the toothed wheel of the direction-selecting unit (85); and

a second spring (73) compressed between the second toothed wheel (90) of the first transmitting unit and the toothed wheel of the direction-selecting unit (85).

8. The wrench according to claim5, wherein the second transmitting unit comprises:

grooves (33) defined in an internal side of the head (30); and

blocks (87) formed on the toothed wheel (85) of the direction-selecting unit and movably located in the grooves (33).

Ansprüche

1. Schlüssel, der umfasst:

einen Griff (10);

einen Bügel (20);

einen Schaft (11), der einen ersten fest mit dem Griff verbundenen Bereich und einen zweiten drehbar in den Bügel (20) eingesetzten Bereich umfasst;

einen Kopf (30), der drehbar mit dem Bügel (20) verbunden ist;

eine Spindel (40), die durch den Kopf hindurch geführt ist (30);

eine erste Übertragungseinheit zum Übertragen eines kleinen Drehmoments von dem relativ zum Bügel (20) gedrehten Griff (10) auf die Spindel (40);

eine zweite mit der ersten Übertragungseinheit verbundene Übertragungseinheit zum Übertragen eines großen Drehmoments von dem zusammen mit dem Bügel (20) gedrehten Griff (10) auf die Spindel (40);

einen Stift (24), der ein erstes in den Bügel (20) eingeführtes Ende und ein zweites in den Kopf (30) eingeführtes Ende umfasst; und

eine Achse (15), die ein erstes in den Bügel (20) eingeführtes Ende und ein zweites in den Kopf (30) eingeführtes Ende umfasst, wobei die erste Übertragungseinheit umfasst:

ein Zahnrad (80), das sicher um die Spindel (40) herum angebracht ist und mit der Achse (15) im Eingriff steht; und

einen Getriebezug (12), der ein erstes sicher angebrachtes, um den Schaft herum vorgesehenes Getrieberitzel und ein letztes sicher angebrachtes, um die Achse (15) herum vorgesehenes Getrieberitzel umfasst,

dadurch gekennzeichnet, dass die zweite Übertragungseinheit ein Zahnrad (85) umfasst, das mit dem Zahnrad (80) der ersten Übertragungseinheit in Eingriff steht und nicht drehbar mit dem Kopf (30) verbunden ist.

2. Schlüssel nach Anspruch 1, bei welchem der Kopf (30) eine an einer inneren Seite vorgesehene Nut (33) umfaßt und bei welchem das Zahnrad (85) der zweiten Übertragungseinheit in der Nut (88) des Kopfs angeordnete Blöcke umfasst.

3. Schlüssel nach Anspruch 1, der eine Richtungswähleinheit (50) umfasst, die bedient werden kann, um eine von zwei Richtungen auszuwählen, in die der Schlüssel das Befestigungselement dreht.

4. Schlüssel nach Anspruch 3, bei welchem die Richtungswähleinheit (50) ein Zahnrad umfasst, das zwischen einer ersten Position und einer zweiten Position in dem Kopf (30) beweglich ist und das mit einer ersten Gruppe von Sperrvorrichtungen auf einer Seite und mit einer zweiten Gruppe von Sperrvorrichtungen auf einer gegenüberliegenden Seite ausgebildet ist, und bei welchem die erste Übertragungseinheit umfasst:

ein erstes Zahnrad (80), das sicher um die Spindel (40) herum angebracht ist und das mit einer Gruppe von Sperrvorrichtungen ausgebildet ist, um mit der ersten Gruppe von Sperrvorrichtungen des Zahnrads der Richtungswähleinheit in der ersten Position in Eingriff zu kommen;

ein zweites Zahnrad (90), das sicher um die Spindel (40) herum angebracht ist und mit einer Gruppe von Sperrvorrichtungen ausgebildet ist, um mit der zweiten Gruppe von Sperrvorrichtungen des Zahnrads der Richtungswähleinheit in der zweiten Position in Eingriff zu kommen; und

einen Getriebezug (12), der ein erstes sicher um den Schaft herum angebrachtes Zahnrad und ein letztes sicher um die Achse (15) herum angebrachtes Zahnrad umfasst.

5. Schlüssel nach Anspruch 4, bei welchem die Richtungswähleinheit (50) umfasst:

einen Drehknopf (51), der drehbar an dem Kopf (30) angeordnet ist und der an einer Seite mit Keilen (57) ausgebildet ist; und

einen Stößel (56), der beweglich aber nicht drehbar in dem Kopf (30) angeordnet ist und mit Keilen (57), die mit den Keilen (57) des Drehknopfs in Eingriff stehen, und mit Beinen (58) ausgebildet ist, die mit dem Zahnrad der Richtungswähleinheit in Kontakt stehen.

6. Schlüssel nach Anspruch 5, der eine mit der Richtungswähleinheit (50) zusammen wirkende Kupplung (70) umfaßt, um das Zahnrad der l2ichtungswähleinheit gleichmäßig zwischen einer ersten und zweiten Position zu bewegen.

7. Schlüssel nach Anspruch 6, bei welchem die Kupplung (70) umfasst:

eine erste Feder (72), die zwischen dem ersten Zahnrad (80) der ersten Übertragungseinheit und dem Zahnrad der Richtungswäbleinkxeit (85) zusammengedrückt wird;

eine zweite Feder (73), die zwischen dem zweiten Zahnrad (90) der ersten Übertragungseinheit (90) und dem Zahnrad der Richtungswähleinheit (85) zusammengedrückt wird.

8. Schlüssel nach Anspruch 5, bei welchem die zweite Übertragungseinheit umfasst::

Nuten (33), die an einer inneren Seite des Kopfes (30) vorgesehen sind; und

Blöcke (87), die an dem Zahnrad der Richtungswähleinheit (85) ausgebildet sind und die beweglich in den Nuten (33) angeordnet sind.

Revendications

1. Clé comprenant :

une poignée (10) ;

un bâti (20) ;

une tige (11) comprenant une première section reliée solidement à la poignée et une seconde section insérée de manière rotative dans le bâti (20) ;

une tête (30) reliée de manière pivotante au bâti (20) ; un mandrin (40) inséré à travers la tête (30) ;

une première unité de transmission pour transmettre une petite force de torsion au mandrin (40) à partir de la poignée (10) en vrille par rapport au bâti (20) ;

une seconde unité de transmission en coopération avec la première unité de transmission pour transmettre une grande force de torsion au mandrin (40) à partir de la poignée (10) pivotée ensemble avec le bâti (20) ;

une broche (24) comprenant une première extrémité insérée dans le bâti (20) et une seconde extrémité insérée dans la tête (30) et

un axe (15) comprenant une première extrémité insérée dans le bâti (20) et une seconde extrémité insérée dans la tête (30), la première unité de transmission comprenant :

une roue dentée (80) prévue solidement autour du mandrin (40) et en prise avec l'axe (15) et

un train d'engrenages (12) comprenant un premier engrenage prévu solidement autour de la tige et un dernier engrenage prévu solidement autour de l'axe (15),

caractérisée en ce que la seconde unité de transmission comprend une roue dentée (85) en prise avec la roue dentée (80) de la première unité de transmission et reliée de manière non rotative à la tête (30).

2. Clé selon la revendication 1 dans laquelle la tête (30) comprend des rainures (33) définies dans un côté interne et la roue dentée (85) de la seconde unité de transmission comprend des blocs (87) situés dans les rainures (88) de la tête.

3. Clé selon la revendication 1 comprenant une unité de sélection de direction (50) prête à être mise en service pour choisir parmi deux directions dans lesquelles la clé tourne l'élément de fixation.

4. Clé selon la revendication 3 dans laquelle l'unité de sélection de direction (50) comprend une roue dentée mobile entre une première position et une seconde position dans la tête (30) et formée avec un premier groupe de cliquets sur un côté et un second groupe de cliquets sur un côté opposé et la première unité de transmission comprend :

une première roue dentée (80) prévue solidement autour du mandrin (40) et formée avec un groupe de cliquets pour se mettre en prise avec le premier groupe de cliquets de la roue dentée de l'unité de sélection de direction dans la première position ;

une seconde roue dentée (90) prévue solidement autour du mandrin (40) et formée avec un groupe de cliquets pour se mettre en prise avec le second groupe de cliquets de la roue dentée de l'unité de sélection de direction (50) dans la seconde position ;

un train d'engrenages (12) comprenant un premier engrenage prévu solidement autour de la tige et un dernier engrenage prévu solidement autour de l'axe (15).

5. Clé selon la revendication 4 dans laquelle l'unité de sélection de direction (50) comprend :

un bouton (59) prévu de manière rotative sur la tête (30) et formé avec des coins (57) sur un côté et

un poussoir (56) situé de manière mobile mais non rotative dans la tête (50) et formé avec des coins (57) en prise avec les coins (57) du bouton (51) et des jambages (58) en contact avec la roue dentée de l'unité de sélection de direction.

6. Clé selon la revendication 5 comprenant un accouplement (70) en coopération avec l'unité de sélection de direction (50) pour déplacer en douceur la roue dentée de l'unité de sélection de direction entre la première et la seconde position.

7. Clé selon la revendication 6 dans laquelle l'accouplement (70) comprend :

un premier ressort (72) comprimé entre la première roue dentée (80) de la première unité de transmission et la roue dentée de l'unité de sélection de direction (85) et

un second ressort (73) comprimé entre la seconde roue dentée (90) de la première unité de transmission et la roue dentée de l'unité de sélection de direction (85).

8. Clé selon la revendication 5 dans laquelle la seconde unité de transmission comprend :

des rainures (33) définies dans un côté interne de la tête (30) et

des blocs (87) formés sur la roue dentée (85) de l'unité de sélection de direction et situés de manière mobile dans les rainures (33).

Drawing